An assessment of water quality on Little and Big Duck Creeks near Elwood, Indiana

Abstract:

A water quality study was conducted on Big Duck Creek and Little Duck Creek near Elwood, Indiana during the summer, autumn and winter of 1978 - 1979 and compared to measurements made in 1938.Samples were analyzed for dissolved oxygen, biochemical oxygen demand, suspended solids, ammonia, total coliform bacteria, hydrogen ion concentration and temperature. Significant differences in concentrations were observed for each environmental parameter measured in 1979 when evaluated on a basis of sampling location. With the exception of dissolved oxygen concentrations, the effect of stream volume on the concentration of environmental parameters was in most instances small.When the up and downstream stations were compared, a definite decrease in water quality was noted. The dissolved oxygen concentrations decreased as the water flowed through the city. Due to increased organic loading, the biochemical oxygen demand increased in the downstream area.Elwood increased the suspended solids level of Big Duck Creek. Agricultural and urban runoff together with untreated sewage discharges significantly increased the suspended solids level within the inner city region. Dilution by treated sewage as well as cleaner water from Little Duck Creek help reduce the suspended solids level in the downstream location. Relatively high ammonia concentrations were observed in the upstream portions of the creeks. This was apparently related to farm practices. The higher readings of ammonia were noted after animal manure was spread on the fields along the stream. The downstream levels were also high. This was probably due to ammonia in the effluents of the sewage treatment plant. In contrast, only small changes in the hydrogen ion concentration was observed throughout the creek.The number of total coliform bacteria increased in the center of town because of a sewer bypass into the creek. Below Elwood the concentration of bacteria decreased due to dilution with disinfected effluents from the sewage treatment plant.Except for a noticeable increase in biochemical oxygen demand and ammonia, the Elwood sewage treatment plant effluent together with flow from Little Duck Creek appears to improve Big Duck Creek's condition as it leaves the city to join White River.Significant differences were observed between measurements made in 1938 and 1978 - 79. Results of the study showed a significant improvement in water quality of Big Duck Creek since 1938. This was probably due to the construction of Elwood's wastewater collection system and sewage treatment plant in the 1940s.However, there was still degradation of water quality within the city due to untreated wastewater discharges. Consequently, emphasis should be focused on the inner city problem since Elwood residents would be in the proximity to this area.